车西洼陷沙四上亚段特低渗储层物性主控因素分析

车西洼陷沙四上亚段碎屑岩储层以含泥细砂岩为主,孔隙度多集中在10%～20%,渗透率多小于10×10-3μm2,结合铸体薄片、压汞、地化测试分析等综合评价为中-低孔特低渗较差储层.研究表明,该区储层物性主要受沉积、成岩和异常高压3种因素控制:1)沉积微相主控储层砂体空问展布形态及孔陈度分布特征;2)成岩作用主控储层砂体孔...

Analysis on controlling factors for ultra-low permeability reservoirs of upper Es4 member in Chexi Depression

Detrital rock reservoir of upper Es4 member in Chexi Depression is mainly shaly fine sandstone,with porosity being 10%-20% mostly and with permeability less than 10 md.Combined with the analysis of casting thin section,mercury injection and geochemistry test,the reservoir is evaluated as middle-low porosity and ultra-low permeability reservoir.The study shows that the reservoir property is mainly controlled by sedimentary microfacies,diagenesis and abnormal overpressure.The spatial distribution and porosity distribution of reservoir sandstones are mainly controlled by sedimentary microfacies.Disgenesis dominates the pore throat structure evolution and permeability distribution of sand body.Abnormal overpressure has an equal effect on porosity and permeability and is corresponding with the depth zone of abnormal high value of both.The differences of three controlling factors to the effect degree of porosity and permeability of ultra-low permeability reservoirs and the effect of the overpressure in different reservoir development stages on the combination characteristics of pore structure require to be studied further,which will create the great effect for the exploration and development of similar reservoirs.